Electrostatic chuck apparatus

ABSTRACT

Disclosed is an electrostatic chuck apparatus which is configured of: an electrostatic chuck section; an annular focus ring section provided to surround the electrostatic chuck section; and a cooling base section which cools the electrostatic chuck section and the focus ring section. The focus ring section is provided with an annular focus ring, an annular heat conducting sheet, an annular ceramic ring, a nonmagnetic heater, and an electrode section that supplies power to the heater.

CROSS REFERENCE FOR RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.13/513,380 entitled “ELECTROSTATIC CHUCK APPARATUS” filed on Jul. 25,2012 (pending), which is a 371 of International Patent ApplicationSerial No. PCT/JP2010/072008 filed on Dec. 8, 2010, which claimspriority to Japanese Patent Application No. 2009-280672, filed on Dec.10, 2009, the disclosures of which are hereby incorporated by referenceherein.

TECHNICAL FIELD

The present invention relates to an electrostatic chuck apparatus, morespecifically, to an electrostatic chuck apparatus which is suitable forbeing used in a plasma processing apparatus of a high frequencydischarge type which applies a high frequency to an electrode togenerate a plasma, and performs a plasma processing such as a plasmaetching on a plate-like specimen such as a semiconductor wafer by theplasma.

Priority is claimed on Japanese Patent Application No. 2009-280672 filedin the Japanese Patent Office on Dec. 10, 2009, the contents of whichare incorporated herein by reference.

BACKGROUND ART

In the related art, in the processing such as an etching, a deposition,an oxidation, and a sputtering in a manufacturing process of asemiconductor device such as an IC, an LSI, and a VLSI, a flat paneldisplay (FPD) such as a liquid crystal display or the like, plasma hasbeen widely used in order to perform a satisfactory reaction on aprocessing gas at a relatively low temperature.

For example, in the etching process of a semiconductor device using asilicon wafer, a plasma etching apparatus of a high frequency dischargetype is used.

However, in the plasma etching apparatus, a phenomenon occurs in whichetching characteristics in a center section of the silicon wafer aredifferent from etching characteristics in an outer periphery portion ofthe silicon wafer.

Thus, in order to equalize the etching characteristics of the siliconwafer in a plane, placing a focus ring having an annular shape on theoutside of the silicon wafer has been carried out so as to surround thesilicon wafer.

However, even in a case of using the focus ring, when the plasma etchingis performed on the silicon wafer, a temperature difference is generatedbetween the center section of the silicon wafer and the outer peripheryportion thereof, and a difference between an etching rate in the centersection of the silicon wafer and an etching rate in the outer peripheryportion thereof is generated due to the temperature difference.

In such a case, there has been a problem in that a state is generatedwhere an etching result in the surface of the silicon wafer isnon-uniform, and thus yield characteristics of the obtainedsemiconductor device decline by the non-uniformity of the in-planeprocessing shape due to the etching.

In order to solve the problem, a plasma etching processing apparatus ofa magnetron type is suggested in which a temperature detector is placednear a surface of an inner portion of a focus ring without being exposedto the surface (Patent Document 1).

In the plasma etching processing apparatus, the temperature of the focusring is detected at all times by the temperature detector, thetemperature of the focus ring is controlled so as to be maintained atthe same temperature as that of the silicon wafer by performing thetemperature controlling of the focus ring. Thus, a difference in surfacereaction of a radical between on the silicon wafer and on the focus ringis suppressed, a fluctuation in the etching rate in the plane of thesilicon wafer is suppressed, and the uniformity of the etching isimproved.

CITATION LIST Patent Document

[Patent Document 1] Japanese Unexamined Patent Application, FirstPulication No. 2002-164323

SUMMARY OF INVENTION Technical Problem

However, in the plasma etching processing apparatus in which thetemperature detector is provided in the focus ring of the related artmentioned above, in a case where the silicon wafer is emitted with theplasma, a temperature rising rate on the surface of the focus ring dueto the plasma irradiation is slower than the temperature rising rate inthe plane of the silicon wafer. Thus, in an initial stage of the plasmairradiation, the surface temperature of the focus ring is suppressed tobe lower than the surface temperature of the silicon wafer, and in afinal stage of the plasma irradiation, on the contrary, the surfacetemperature of the focus ring becomes higher than the surfacetemperature of the silicon wafer. Accordingly, there has been a problemin that, since the temperature difference is generated between the focusring and the silicon wafer, as a consequence, the in-plane temperatureof the silicon wafer is not also stable.

Furthermore, in the plasma etching processing apparatus, it is alsopossible to cool the focus ring by the use of the cooler whenirradiating the plasma, but, in this case, it is difficult to adjust thetemperature rising due to the plasma irradiation of the focus ring bythe cooler, and it is difficult to accurately adjust the surfacetemperature of the focus ring.

In this manner, there has been a problem in that, even in the case ofproviding the temperature detector in the focus ring, a state isgenerated where the etching result in the plane of the silicon wafer isnon-uniform, and thus the yield characteristics of the obtainedsemiconductor wafer decline by the non-uniformity of the in-planeprocessing shape due to the etching.

In addition, since the adjustment of the surface temperature of thefocus ring is difficult, in a case where the surface temperature of thefocus ring is lower than the surface temperature of the silicon wafer,there has been a problem in that the deposits are easily deposited onthe focus ring.

The present invention has been made in view of the above circumstances,and an object thereof is to provide an electrostatic chuck apparatuswhich is able to maintain the constant temperature of the focus ringbeing processed, by adjusting the temperature of the focus ring providedso as to surround the plate-like specimen such as the silicon wafer whenbeing applied to the processing apparatus such as the plasma etchingapparatus, is able to stabilize the temperature of the outer peripheryportion of the plate-like specimen, is able to equalize the etchingcharacteristics in the plane of the plate-like specimen, and is able toprevent the deposits from being deposited on the focus ring.

Solution to Problem

As a result of intensive studies in order to solve the problemsmentioned above, the present inventors discovered that, if the annularfocus ring section provided so as to surround the electrostatic chucksection has a configuration that includes a focus ring, a ceramic plate,a heater section formed from a non-magnetic body and an electrodesection supplying electricity to the heater section, the temperature ofthe focus ring section being processed can be maintained constantly byadjusting the temperature of the focus ring section, the temperature ofthe outer periphery portion of the plate-like specimen such as thesilicon wafer can be stabilized, the etching characteristics in theplane of the plate-like specimen can be uniform, and it is possible toprevent the deposits from being deposited on the focus ring section.Thus, the present invention was completed.

That is, an electrostatic chuck apparatus according to the presentinvention includes the aspects as below.

<1> An electrostatic chuck apparatus which includes an electrostaticchuck section, one main surface of which is a placing surface forplacing a plate-like specimen, and which is equipped with an internalelectrode for electrostatic adsorption; an annular focus ring sectionprovided so as to surround the electrostatic chuck section; and acooling base section which is provided on the other main surface side ofthe electrode chuck section to cool the electrostatic chuck section andthe focus ring section, wherein the focus ring section includes a focusring, a ceramic plate which is provided between the focus ring and thecooling base section, a heater section which is provided between theceramic plate and the cooling base section and is formed from anon-magnetic body, and an electrode section which supplies electricityto the heater section.

<2> The electrostatic chuck apparatus according to <1>, wherein theceramic plate is constituted by any one kind of an annular ceramicplate, a plurality of ceramic pieces formed by dividing the annularceramic plate in a circumferential direction, and a plurality of annularceramic pieces formed by dividing the annular ceramic plate in a radialdirection.

<3> The electrostatic chuck apparatus according to <1> or <2>, whereinthe heater section is a sheet-like heater portion.

<4> The electrostatic chuck apparatus according to any one of <1> to<3>, wherein the heater section is fixed to the ceramic plate by a firstinsulating adhesive layer, is fixed to the cooling base section by asecond insulating adhesive layer, and is insulated by the firstinsulating adhesive layer and the second insulating adhesive layer.

<5> The electrostatic chuck apparatus according to any one of <1> to<4>, wherein an insulating ceramic membrane or an insulating organicfilm is provided between the cooling base section and the heatersection.

<6> The electrostatic chuck apparatus according to any one of <1> to<5>, wherein temperature measuring means is provided in the focus ringsection.

<7> The electrostatic chuck apparatus according to any one of <1> to<6>, wherein the heater section has an electrical conductivity of0.5×106 S/m or more and 20×106 S/m or less, and a coefficient of thermalexpansion of 0.1×10-6/K or more and 100×10-6/K or less.

<8> The electrostatic chuck apparatus according to any one of <1> to<7>, wherein the heater section is formed from titanium or titaniumalloy.

<9> The electrostatic chuck apparatus according to any one of <1> to<8>, wherein the ceramic plate has insulating properties and has athermal conductivity of 1 W/mK or more.

<10> The electrostatic chuck apparatus according to any one of <1> to<9>, wherein the coefficient of heat transfer between the heater sectionand the cooling base section is 400 W/m2K or more and 10,000 W/m2K orless.

Advantageous Effects of Invention

According to the electrostatic chuck apparatus of the present invention,the annular focus ring section is provided so as to surround theelectrostatic chuck section, and the focus ring section is constitutedby the focus ring section, the ceramic plate provided between the focusring and the cooling base section, the heater formed from thenon-magnetic body provided between the ceramic plate and the coolingbase section, and the electrode supplying electricity to the heatersection. Thus, by adjusting the temperature of the focus ring section bythe heater, the temperature of the focus ring section being processedcan be maintained constantly. Accordingly, the temperature of the outerperiphery portion of the plate-like specimen such as the silicon wafercan be stabilized, and thus, the etching characteristics in the plane ofthe plate-like specimen can be equalized.

Furthermore, since the surface temperature of the focus ring can beaccurately adjusted, the temperature difference between the surfacetemperature of the focus ring and the surface temperature of theplate-like specimen can be eliminated, whereby it is possible to preventthe deposits from being deposited on the focus ring.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view that shows an electronic chuckapparatus of an embodiment of the present invention.

FIG. 2 is a plan view that shows an example of a shape of a ceramic ringof the electronic chuck apparatus of an embodiment of the presentinvention.

FIG. 3 is a plan view that shows another example of the shape of theceramic ring of the electrostatic chuck apparatus of an embodiment ofthe present invention.

FIG. 4 is a plan view that shows still another embodiment of the shapeof the ceramic ring of the electrostatic chuck apparatus of anembodiment of the present invention.

FIG. 5 is a cross-sectional view that shows a modified example of theelectrostatic chuck apparatus of an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

An embodiment of an electrostatic chuck apparatus of the presentinvention will be described.

In addition, in the respective embodiments mentioned below will bespecifically described in order to better understand the spirit of thepresent invention, but the present invention is not limited, unlessotherwise particularly specified.

FIG. 1 is a cross-sectional view that shows an electrostatic chuckapparatus of an embodiment of the present invention, and theelectrostatic chuck apparatus 1 is constituted by an electrostatic chucksection 2, an annular focus ring section 3 provided so as to surroundthe electrostatic chuck section 2, and a cooling base section 4 whichcools the electrostatic chuck section 2 and the focus ring section 3.

The electrostatic chuck section 2 includes a circular dielectric layer11 in which an upper surface (one major surface) thereof is a placingsurface for placing a plate-like specimen W such as a semiconductorwafer, a circular insulating layer 12 which is oppositely arranged on alower surface (the other major surface) side of the dielectric layer 11and has the same diameter as that of the dielectric layer 11, anelectrostatic adsorption internal electrode 13 of an annular shape whichis interposed between the dielectric layer 11 and the insulating layer12 and has a diameter smaller than those of the dielectric layer 11 andthe insulating layer 12, an annular insulating material layer 14provided on the outer periphery side of the electrostatic adsorptioninternal electrode 13 so as to surround the same, a power supplyingterminal 15 which is connected to a lower surface center portion of theelectrostatic adsorption internal electrode 13 to apply the directcurrent voltage, and a cylindrical insulator 16 which is isolated fromthe outside by covering the periphery of the power supplying terminal15.

Preferably, both of the dielectric layer 11 and the insulating layer 12are ceramics having the heat resistance. As the ceramics, ceramicsformed of one kind selected from aluminum nitride (AlN), aluminum oxide(Al2O3), silicon nitride (Si3N4), zirconium oxide (ZrO2), sialon, boronnitride (BN), silicon carbide (SiC), or composite ceramics including twokinds or more are preferably used.

Particularly, in view of the fact that upper surface 11 a becomes anelectrostatic adsorption surface, the dielectric layer 11 is made from amaterial which has a particularly high dielectric constant, and does notbecome impurities with respect to the electrostatically adsorbedplate-like specimen W. For example, silicon carbide-aluminum oxidecompound sintered compact is preferably used which contains siliconcarbide of 4 weight % or more and 20 weight % or less and the remaindersof aluminum oxide.

As the electrostatic adsorption internal electrode 13, a flat plateceramic having a thickness of about 10 μm to 50 μm and conductivity isused. A volume resistivity value of the electrostatic adsorptioninternal electrode 13 under the working temperature of the electrostaticchuck apparatus 1 is preferably equal to or less than 1.0×106 Ω·cm, andmore preferably, is equal to or less than 1.0×104 Ω·cm.

As the conductive ceramics constituting the electrostatic adsorptioninternal electrode 13, silicon carbide (SiC)—aluminum oxide (Al2O3)compound sintered compact, tantalum nitride (TaN)—tantalum oxide (Al2O3)compound sintered compact, tantalum carbide (TaC)—aluminum oxide (Al2O3)compound sintered compact, molybdenum carbide (Mo2C)—aluminum oxide(Al2O3) compound sintered compound or the like are adopted.

The insulating material layer 14 joins the dielectric layer 11 and theinsulating layer 12 to integrate them, and protects the electrostaticadsorption internal electrode 13 from the plasma. As a materialconstituting the insulating material layer 14, an insulating materialhaving the same main component as those of the dielectric layer 11 andthe insulating layer 12 is preferably used. For example, when thedielectric layer 11 and the insulating layer 12 are formed by siliconcarbide-aluminum oxide compound sintered compact, aluminum oxide (Al2O3)is preferably used.

The focus ring section 3 includes a focus ring 21 formed from an annularplate material which has an inner diameter slightly larger than adiameter of the electrostatic chuck section 2 and an outer diameterslightly larger than an outer diameter of the cooling base section 4; anannular thermal conducting sheet 22 which is adhered to a lower surfaceof the focus ring 21 and has an inner diameter identical to the innerdiameter of the focus ring 21 and an outer diameter smaller than theouter diameter of the focus ring 21; an annular ceramic ring (a ceramicplate) 23 which is adhered to a lower surface of the thermal conductingsheet 22 and has an inner diameter and an outer diameter substantiallyidentical to those of the thermal conducting sheet 22; a heater 25 whichis adhered to the lower surface of the ceramic ring 23 via a sheet-like(first) insulating adhesive layer 24 and is formed from a non-magneticbody; a heater electrode 26 which is bonded to the lower surface of theheater 25 to supply electricity to the heater 25; and a cylindricalheater insulator 27 which is isolated from the outside by covering theperiphery of the heater electrode 26.

The focus ring section 3 is bonded and fixed to the cooling base section4 via a (second) insulating adhesive layer 28.

The focus ring 21 is controlled so as to be the same temperature as thatof the plate-like specimen W by a processing step such as a plasmaetching. As the material thereof, for example, in a case of being usedin oxide film etching, polycrystalline silicon, silicon carbide or thelike are suitably used.

The thermal conducting sheet 22 transmits heat from the ceramic ring 23subjected to the temperature control to the focus ring 21, and asheet-like material having high thermal conductivity or the like issuitably used.

In order that the thermal conducting sheet 22 continues to favorablyhold the thermal conduction between the focus ring 21 and the ceramicring 23, it is necessary that the coefficient of heat transfer in thecase of interposing the thermal conducting sheet 22 between the focusring 21 and the ceramic ring 23 be equal to or greater than 500 W/m2K.

Herein, in a case where the coefficient of heat transfer is less than500 W/m2K, an influence of the temperature rising of the focus ring 21is increased when high frequency is applied, it is impossible to controlthe temperature of the focus ring 21 due to the heater 25 and thecooling base section 4, and the case is not preferable.

The ceramic ring 23 is, for example, an annular ceramic plate havinginsulating properties formed from aluminum oxide (Al2O3), quartz or thelike, and the thermal conductivity thereof is equal to or greater than 1W/mK.

When the thermal conductivity is less than 1 W/mK, heat from the heater25 cannot be rapidly transmitted to the focus ring 21 via the thermalconducting sheet 22, a temperature difference is generated between thesurface temperature of the focus ring 21 and the surface temperature ofthe electrostatic chuck section 2, and thus, the surface temperature ofthe plate-like specimen W placed on the electrostatic chuck section 2 isnot stable. As a consequence, it is impossible to equalize the in-planecharacteristics of the plate-like specimen W subjected to variousprocesses, and the case is not preferable.

In addition to the annular shape shown in FIG. 2, the ceramic ring 23may be an arc-shaped ceramic piece in which the annular ceramic plate isdivided into a plurality of parts in a circumferential direction, forexample, the arc-shaped ceramic pieces 23 a to 23 d shown in FIG. 3 maybe combined with each other in an annular shape, an annular ceramicpieces may be used in which the annular ceramic piece is divided into aplurality of parts in a radial direction, for example, annular ceramicpieces 23 e to 23 f shown in FIG. 4 may be concentrically combined witheach other.

As the insulating adhesive layers 24 and 28, the adhesive having theheat resistance in the temperature range of −20° C. to 150° C. issuitably used. For example, silicon resin, silicon resin containing afiller such as alumina and aluminum nitride, acryl resin, epoxy resin orthe like are preferable. Particularly, in the case of using theoxygen-based plasma, silicon resin having an excellent plasma resistancewith respect to the oxygen-based plasma is preferable.

The insulating adhesive layers 24 and 28 may be the same material andmay be materials different from each other. Furthermore, the shapesthereof may be the sheet-like adhesive, and a liquid adhesive or thelike may be adopted which is cured by heat and an ultravioletirradiation. In brief, the insulating adhesive layers may be suitablyselected and used according to the material composition and the shape ofa member to be bonded.

Specifically, for example, the insulating adhesive layer 24 ispreferably the sheet-like epoxy resin, and the insulating adhesive layer28 is preferably the silicon resin.

The heater 25 controls the temperature of the focus ring 21 to the sametemperature as that of the plate-like specimen W, by heating thetemperature of the focus ring 21 to a predetermined temperature at acertain temperature rising rate via the ceramic ring 23. In order tosufficiently demonstrate the function as the heater 25, electricalconductivity thereof is preferably 0.5×106 S/m or more and 20×106 S/m orless, and, more preferably, 0.9×106 S/m or more and 5×106 S/m or less.

Furthermore, even in a case where the heating and the cooling arerepeated, it is necessary that the heater 25 does not peel off from theceramic ring 23 and the cooling base section 4. Thus, coefficient ofthermal expansion thereof is preferably 0.1×10-6/K or more and100×10-6/K or less, more preferably, 0.1×10-6/K or more and 20×10-6/K orless, and, still more preferably, 4×10-6/K or more and 10×10-6/K orless.

Since the heater itself avoids the self-heating by the high frequency(RF) when the high frequency (RF) is applied in a case of being appliedto a plasma processing apparatus using the high frequency (RF), theheater 25 needs to be a non-magnetic material, and a conductor formedfrom the sheet-like non-magnetic material is suitably used. As such aconductor, for example, a titanium foil, titanium alloy foil or the likeare adopted.

The thickness of the heater 25 is, preferably, equal to or less than 200μm, and, more preferably, equal to or less than 120 μm.

By making the thickness of the heater 25 equal to or less than 200 μm,when bonding and fixing the heater 25 to the cooling base section 4 viathe insulating adhesive layer 28, the thickness of the insulatingadhesive layer 28 from the ceramic ring 23 to the cooling base section 4can be reduced, and thus, it is possible to reduce an area to be exposedto the plasma in an exposed cross-section of the insulating adhesivelayer 28. As a consequence, it is possible to reduce the damage to theinsulating adhesive layer 28 due to the plasma when irradiating theplasma.

The heater 25 is bonded to the lower surface of the ceramic ring 23 viathe insulating adhesive layer 24, and is bonded and fixed to the coolingbase section 4 via the insulating adhesive layer 28. In addition, theheater 25 is held while favorably keeping an interval between them,without coming into contact with the cooling base section 4, and theinsulating adhesive is filled in the gap, and thus, the insulatingproperties between the ceramic ring 23 and the cooling base section 4can be favorably maintained, whereby it is possible to reduce thethermal stress of the heater 25 by the insulating adhesive layers 24 and28.

The cooling base section 4 is provided on the lower sides of theelectrostatic chuck section 2 and the focus ring section 3 to controlthe temperatures of the electrostatic chuck section 2 and the focus ringsection 3 to desired temperatures, combines a high frequency generatingelectrode, and is formed by a metal having good thermal conductivitysuch as aluminum. An inner portion thereof is formed with a flow path 31through which a cooling medium such as water and organic solvent iscirculated. The cooling base section 4 is able to maintain thetemperature of the plate-like specimen W placed on the upper surface 11a of the dielectric layer 11 to a desired temperature.

The heater electrode 26 and the heater insulator 27 are fixed to athrough hole 32 formed on the underside of the heater 25 of the coolingbase section 4, the power supplying terminal 15 and the insulator 16 arefixed to a through hole 33 formed in the center portion of the coolingbase section 4, and an optical thermometer (temperature measuring means)35 for directly measuring the temperature of the ceramic ring 23 byreceiving light emitted from the ceramic ring 23 is fixed to a throughhole 34 of an opposite side of the though hole 32 to the center axis ofthe cooling base section 4.

The optical thermometer 35 may have a configuration that directlymeasures the temperature of the heater 25, and may have a configurationthat directly measures the temperature of the focus ring 21.

A temperature controller 36 and a heater power source 37 are connectedto the optical thermometer 35 in series, and the heater power source 37is connected to the heater electrode 26.

Herein, if one wants to know the temperature of the ceramic ring 23,when the optical thermometer 35 detects light emitted from the ceramicring 23, it is possible to directly know the temperature of the ceramicring 23 from a wavelength band of the light.

Herein, the optical thermometer 35 converts the value of the temperaturecorresponding to the light into an electrical signal and outputs thesignal to the temperature controller 36. In the temperature controller36, the control signal, which controls the electrical power applied tothe heater 25 based on the electrical signal from the opticalthermometer 35, is output to the heater power source 37. In the heaterpower source 37, the controlled electrical power is output to the heater25 based on the control signal which is output from the temperaturecontroller 36, and an amount of heat emitted from the heater 25 iscontrolled.

Thus, the focus ring 21 can be heated up to a predetermined temperatureat a certain temperature rising rate via the ceramic ring 23 by usingthe heater 25, and the temperature can be held. Furthermore, in a casewhere the temperature of the focus ring 21 is increased by the plasma,the temperature rising of the focus ring section 3 is suppressed byadjusting the output of the heater 25, and thus, the temperature of thefocus ring section 3 can be constantly maintained.

An interval between the cooling base section 4 and the ceramic ring 23is a sum of thickness the insulating adhesive layer 24, the heater 25and the insulating adhesive layer 28, that is, 100 μm to 500 μm.

In this manner, by interposing the insulating adhesive layer 24, theheater 25 and the insulating adhesive layer 28 in a layer shape, theinterval between the cooling base section 4 and the ceramic ring 23 canbe extremely narrowed, and thus, the temperature of the focus ring 21can be accurately controlled to a predetermined temperature via theceramic ring 23.

The coefficient of heat transfer between the cooling base section 4 andthe heater 25 is preferably 400 W/m2K or more and 10,000 W/m2K or less,and more preferably, 1,000 W/m2K or more and 4,000 W/m2K or less. Bysetting the coefficient of heat transfer between the cooling basesection 4 and the heater 25 to the range mentioned above, it is possibleto substantially match the temperature rising rate and the cooling rateof the ceramic ring 23 with the temperature rising rate and the coolingrate of the electrostatic chuck section 2 when causing a predeterminedcurrent to flow in the heater 25. Thus, it is possible to substantiallymatch the temperature rising rate and the cooling rate of the focus ring21 with the temperature rising rate and the cooling rate of theelectrostatic chuck section 2.

From the above, the temperature of the focus ring 21 can be adjusted byusing the heater 26, and the temperature of the focus ring 21 beingprocessing can be constantly maintained. Thus, the temperature of theouter periphery portion of the plate-like specimen W such as the siliconwafer can be stabilized, and thus, the etching characteristics in theplane of the plate-like specimen W can be equalized.

Furthermore, since the surface temperature of the focus ring 21 can beaccurately adjusted, it is possible to alleviate the temperaturedifference between the surface temperature of the focus ring 21 and thesurface temperature of the plate-like specimen W placed on theelectrostatic chuck section 2, and thus, it is possible to prevent thedeposits from being deposited on the focus ring 21.

As described above, according to the electrostatic chuck apparatus ofthe present embodiment, since the heater 25 is provided between theceramic ring 23 and the cooling base section 4, it is possible toalleviate the stress to the ceramic ring 23 when the heater 25 generatesheat. Furthermore, since a configuration is used in which the heater 25is not embedded in ceramics, the manufacturing step can be simplified,and the manufacturing cost can also be reduced.

Since the heater 25 is the non-magnetic body, even in a case where thehigh frequency is applied to the heater 25, there is no fear ofgeneration of heat due to the high frequency. Thus, even when the highfrequency is applied, the self generation of heat can be avoided.

Since the heater 25 is fixed to the ceramic ring 23 and the cooling basesection 4 via the insulating adhesive layers 24 and 28, by interposingthe insulating adhesive layers 24 and 28 between the ceramic ring 23 andthe cooling base section 4, the thermal stress due to the thermalexpansion of the heater 25 can be alleviated, and the thermal stress dueto the thermal expansion of the ceramic ring 23 and the cooling basesection 4 can also be alleviated.

In addition, since the optical thermometer 35 for directly measuring thetemperature of the ceramic ring 23 is fixed to the through hole 34 ofthe cooling base section 4, it is possible to prevent the heat of theceramic ring 23 escaping to the cooling base section 4 via the opticalthermometer 35.

Furthermore, since the temperature of the ceramic ring 23 is directlymeasured by the optical thermometer 35, there is no fear of an influenceof the generation of heat from the heater 25, and the temperature of theceramic ring 23 itself can be accurately measured.

In addition, in order to increase insulating properties between thecooling base section 4 and the heater 25, an insulating ceramic membraneor an insulating organic film may be provided between the cooling basesection 4 and the heater 25.

Furthermore, the thermal conducting sheet 22 is provided between thefocus ring 21 and the ceramic ring 23, but a configuration may beadopted in which helium gas or the like flows, instead of the thermalconducting sheet 22.

Furthermore, as a target that directly measures the temperature usingthe optical thermometer 35, the temperature of the focus ring 21 or thethermal conducting sheet 22 may be directly measured, without beinglimited to the ceramic ring 23.

FIG. 5 is a cross-sectional view that shows a modified example of theelectrostatic chuck apparatus of the present embodiment. Theelectrostatic chuck apparatus 41 is different from the electrostaticchuck apparatus 1 in that the cooling base section is divided into adisk-shaped thick cooling base section 42 for cooling the electrostaticchuck section 2 and an annular thick cooling base section 43 provided soas to surround the cooling base section 42 for cooling the focus ringsection 3. In other respects, the electrostatic chuck apparatus 41 isexactly the same as the electrostatic chuck apparatus 1 mentioned above.

According to the electrostatic chuck apparatus 41, since the thickcooling base section 42 for cooling the electrostatic chuck section 2and the cooling base section 43 for cooling the focus ring section 3 areprovided, the electrostatic chuck section 2 can be cooled by the coolingbase section 42, and the focus ring section 3 can be cooled by thecooling base section 43, respectively and independently, whereby it ispossible to enhance the temperature controllability of each of theelectrostatic chuck section 2 and the focus ring section 3.

REFERENCE SIGNS LIST

1: electrostatic chuck apparatus

2: electrostatic chuck section

3: focus ring section

4: cooling base section

11: dielectric layer

11 a: upper surface

12: insulating layer

13: electrostatic adsorption internal electrode

14: insulating material layer

15: power supplying terminal

16: insulator

21: focus ring

22: thermal conducting sheet

23: ceramic ring (ceramic plate)

24: (first) insulating adhesive layer

25: heater

26: heater electrode

27: heater insulator

28: (second) insulating adhesive layer

31: flow path

32 to 34: through hole

35: optical thermometer (temperature measuring means)

36: temperature controller

37: heater power source

41: electrostatic chuck apparatus

42, 43: cooling base section

The invention claimed is:
 1. An electrostatic chuck apparatuscomprising: an electrostatic chuck section, one main surface of which isa placing surface for placing a specimen, and which is equipped with aninternal electrode for electrostatic adsorption; an annular focus ringsection which is provided so as to surround the electrostatic chucksection; a cooling base section which is provided on the other mainsurface side of the electrode chuck section to cool the electrostaticchuck section and the focus ring section, the focus ring sectionincludes an annular focus ring, an annular ceramic plate which isadhered to a lower surface of the focus ring, a sheet-like heaterportion which is provided between the annular ceramic plate and thecooling base section, and is formed from a non-magnetic metal, and anelectrode section which supplies electricity to a heater section, theheater section is fixed to the annular ceramic plate by a firstinsulating adhesive layer, is fixed to the cooling base section by asecond insulating adhesive layer, and is insulated by the firstinsulating adhesive layer and the second insulating adhesive layer, anda cooling medium gas is circulated between the annular focus ringsection and the annular ceramic plate.
 2. The electrostatic chuckapparatus according to claim 1, wherein the annular ceramic plate isconstituted by a plurality of annular ceramic pieces which is formed bydividing the annular ceramic plate in a radial direction.
 3. Theelectrostatic chuck apparatus according to claim 1, wherein aninsulating ceramic membrane or an insulating organic film is providedbetween the cooling base section and the heater section.
 4. Theelectrostatic chuck apparatus according to claim 1, wherein temperaturemeasuring means is provided in the focus ring section.
 5. Theelectrostatic chuck apparatus according to claim 1, wherein the heatersection has an electrical conductivity of 0.5×10⁶ S/m or more and 20×10⁶S/m or less, and a coefficient of thermal expansion of 0.1×10⁻⁶/K ormore and 100×10⁻⁶/K or less.
 6. The electrostatic chuck apparatusaccording to claim 1, wherein the heater section is formed from titaniumor titanium alloy.
 7. The electrostatic chuck apparatus according toclaim 1, wherein the ceramic plate has insulating properties and hasthermal conductivity of 1 W/mK or more.
 8. The electrostatic chuckapparatus according to claim 1, wherein the second insulating adhesivelayer contains a filler.
 9. The electrostatic chuck apparatus accordingto claim 1, wherein the coefficient of heat transfer between the heatersection and the cooling base section is 400 W/m²K or more and 10,000W/m²K or less.
 10. An electrostatic chuck apparatus comprising: anelectrostatic chuck section, one main surface of which is a placingsurface for electrostatic adsorption of a plate-like specimen, and whichis equipped with an internal electrode for electrostatic adsorption; anannular focus ring section which is provided so as to surround theelectrostatic chuck section; and a cooling base section which isprovided on the other main surface side of the electrode chuck sectionto cool the electrostatic chuck section and the focus ring section,wherein the focus ring section includes a focus ring, a ceramic platewhich is provided between the focus ring and the cooling base section, aheater section which is provided between the ceramic plate and thecooling base section and is formed from a non-magnetic body, and anelectrode section which supplies electricity to the heater section; thecooling base section is divided into two parts: one part being a firstcooling base section which supports the electrostatic chuck section, andcools the electrostatic chuck section by a flow path through which acooling medium is circulated, and the other part being a second coolingbase section which is present outside of the first cooling base sectionfor supporting the annular focus ring section, and cools the annularfocus ring by another flow path through which a cooling medium iscirculated.
 11. The electrostatic chuck apparatus according to claim 10,wherein the ceramic plate is constituted by a plurality of annularceramic pieces which is formed by dividing the annular ceramic plate ina radial direction.
 12. The electrostatic chuck apparatus according toclaim 10, wherein an insulating ceramic membrane or an insulatingorganic film is provided between the second cooling base section and theheater section.
 13. The electrostatic chuck apparatus according to claim10, wherein temperature measuring means is provided in the focus ringsection.
 14. The electrostatic chuck apparatus according to claim 10,wherein the heater section has an electrical conductivity of 0.5×10⁶ S/mor more and 20×10⁶ S/m or less, and a coefficient of thermal expansionof 0.1×10⁻⁶/K or more and 100×10⁻⁶/K or less.
 15. The electrostaticchuck apparatus according to claim 10, wherein the heater section isformed from titanium or titanium alloy.
 16. The electrostatic chuckapparatus according to claim 10, wherein the ceramic plate hasinsulating properties and has thermal conductivity of 1 W/mK or more.17. The electrostatic chuck apparatus according to claim 10, wherein thecoefficient of heat transfer between the heater section and the coolingbase section is 400 W/m²K or more and 10,000 W/m²K or less.
 18. Theelectrostatic chuck apparatus according to claim 10, wherein the heatersection is fixed to the ceramic plate by a first insulating adhesivelayer, is fixed to the cooling base section by a second insulatingadhesive layer, and is insulated by the first insulating adhesive layerand the second insulating adhesive layer.
 19. The electrostatic chuckapparatus according to claim 18, wherein the second insulating adhesivelayer contains a filler.
 20. The electrostatic chuck apparatus accordingto claim 10, wherein a cooling medium gas is circulated between theannular focus ring section and the annular ceramic plate.